Light-emitting device

ABSTRACT

A light-emitting device includes a semiconductor structure including a first semiconductor layer, a second semiconductor layer, and an active layer formed between the first semiconductor layer and the second semiconductor layer; a via penetrating the second semiconductor layer and the active layer to expose a surface of the first semiconductor layer; a first electrode formed in the via and on the second semiconductor layer; a second electrode formed on the second semiconductor layer; and an insulating structure covering the first electrode, the second electrode and the semiconductor structure and including a first opening to expose the first electrode and a second opening to expose the second electrode, wherein the first electrode and the second electrode respectively include a metal layer contacting the insulating layer, the metal layer includes a material including a surface tension value larger than 1500 dyne/cm and a standard reduction potential larger than 0.3 V.

REFERENCE TO RELATED APPLICATION

This application is a Continuation of co-pending application Ser. No.17/165,290, filed on Feb. 2, 2021, which is a continuation ofapplication Ser. No. 16/877,840, filed on May 19, 2020, which is acontinuation of application Ser. No. 16/416,488, filed on May 20, 2019,which is a continuation of application Ser. No. 15/874,398, filed onJan. 18, 2018, which claims priority of U.S. Provisional Application No.62/450,860 filed on Jan. 26, 2017 under 35 U.S.C. § 119(e), the entirecontents of which are hereby incorporated by reference.

TECHNICAL FIELD

The application relates to a structure of a light-emitting device, andmore particularly, to a light-emitting device including a semiconductorstructure and a pad on the semiconductor structure.

DESCRIPTION OF BACKGROUND ART

Light-Emitting Diode (LED) is a solid-state semiconductor light-emittingdevice, which has the advantages of low power consumption, low heatgeneration, long working lifetime, shockproof, small volume, fastreaction speed and good photoelectric property, such as stable emissionwavelength. Therefore, light-emitting diodes are widely used inhousehold appliances, equipment indicators, and optoelectronic products.

SUMMARY OF THE APPLICATION

A light-emitting device includes a semiconductor structure including afirst semiconductor layer, a second semiconductor layer, and an activelayer formed between the first semiconductor layer and the secondsemiconductor layer; a via penetrating the second semiconductor layerand the active layer to expose a surface of the first semiconductorlayer; a first electrode formed in the via and/or on the secondsemiconductor layer; a second electrode formed on the secondsemiconductor layer; and an insulating structure covering the firstelectrode, the second electrode and the semiconductor structure,including a first opening to expose the first electrode and a secondopening to expose the second electrode, wherein the first electrode andthe second electrode respectively includes a metal layer contacting theinsulating structure, the metal layer includes a material including asurface tension value larger than 1500 dyne/cm and a standard reductionpotential larger than 0.3 V.

A light-emitting device includes a semiconductor structure including afirst semiconductor layer, a second semiconductor layer, and an activelayer formed between the first semiconductor layer and the secondsemiconductor layer; a via penetrating the second semiconductor layerand the active layer to expose a surface of the first semiconductorlayer; a first electrode formed in the via and/or on the secondsemiconductor layer; a second electrode formed on the secondsemiconductor layer; and an insulating structure covering the firstelectrode, the second electrode and the semiconductor structure,including a first opening to expose the first electrode and a secondopening to expose the second electrode, wherein the first electrode andthe second electrode respectively includes a metal layer contacting theinsulating structure, the metal layer includes a material including aYoung's modulus value larger than 100 GPa.

A light-emitting device includes a semiconductor structure including afirst semiconductor layer, a second semiconductor layer, and an activelayer formed between the first semiconductor layer and the secondsemiconductor layer; a via penetrating the second semiconductor layerand the active layer to expose a surface of the first semiconductorlayer; a first electrode formed in the via and on the secondsemiconductor layer; a second electrode formed on the secondsemiconductor layer; an insulating structure covering the firstelectrode, the second electrode and the semiconductor structure, theinsulating structure including a first opening to expose the firstelectrode and a second opening to expose the second electrode; a firstthin pad formed in the first opening, the first thin pad having athickness smaller than a thickness of the insulating structure; and asecond thin pad formed in the second opening, the second thin pad havinga thickness smaller than the thickness of the insulating structure.

A light-emitting device includes a semiconductor structure including afirst semiconductor layer, a second semiconductor layer, and an activelayer formed between the first semiconductor layer and the secondsemiconductor layer; a via penetrating the second semiconductor layerand the active layer to expose a surface of the first semiconductorlayer; a first electrode formed in the via and/or on the secondsemiconductor layer; a second electrode formed on the secondsemiconductor layer; and an insulating structure covering the firstelectrode, the second electrode and the semiconductor structure, theinsulating structure including a first opening to expose the firstelectrode and a second opening to expose the second electrode, whereinthe first electrode and the second electrode are separated apart by adistance smaller than 50 μm.

A light-emitting device includes a semiconductor structure including afirst semiconductor layer, a second semiconductor layer, and an activelayer including a light-emitting area formed between the firstsemiconductor layer and the second semiconductor layer; an openingformed in the semiconductor structure to expose a surface of the firstsemiconductor layer; a first electrode formed in the opening; a secondelectrode formed on the second semiconductor layer; and an insulatingstructure covering the first electrode, the second electrode and thesemiconductor structure, including a first opening to expose the firstelectrode and a second opening to expose the second electrode, whereinthe first electrode and the second electrode occupy 10˜20% of thelight-emitting area of the light-emitting device.

A light-emitting device comprises a substrate; a semiconductor structureformed on the substrate, comprising a first semiconductor layer, asecond semiconductor layer, and an active layer between the firstsemiconductor layer and the second semiconductor layer, wherein thesubstrate comprises an exposed surface not covered by the semiconductorstructure; a part penetrating the second semiconductor layer and theactive layer to expose a first surface of the first semiconductor layer;a first electrode formed on the part, extending from the exposed surfaceof the substrate, along the first surface of the first semiconductorlayer and an outside wall of the second semiconductor layer to overlapthe second semiconductor layer; and a second electrode formed on thesecond semiconductor layer, wherein the first electrode and the secondelectrode are separated apart by a distance smaller than 50 μm.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a top view of a light-emitting devices 1 or 1 a inaccordance with embodiments of the present application;

FIG. 2 illustrates a cross-sectional view of the light-emitting device 1in accordance with an embodiment of the present application;

FIG. 3 illustrates a cross-sectional view of the light-emitting device 1a in accordance with an embodiment of the present application;

FIG. 4 illustrates a top view of a light-emitting device 2 in accordancewith an embodiment of the present application;

FIG. 5 illustrates a schematic view of a light-emitting apparatus 3 inaccordance with an embodiment of the present application; and

FIG. 6 illustrates a structure diagram of a light-emitting apparatus 4in accordance with an embodiment of the present application.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The embodiment of the application is illustrated in detail, and isplotted in the drawings. The same or the similar part is illustrated inthe drawings and the specification with the same number.

FIG. 1 illustrates a top view of the light-emitting devices 1 and 1 a inaccordance with two embodiments of the present application. FIG. 2 is across-sectional view of the light-emitting device 1 taken along lineA-A′ of FIG. 1 in accordance with an embodiment of the presentapplication. FIG. 3 is a cross-sectional view of the light-emittingdevice 1 a taken along line A-A′ of FIG. 1 in accordance with anotherembodiment of the present application. Each of the light-emittingdevices 1 and 1 a disclosed in the present embodiment is a flip chiplight-emitting diode. The light-emitting devices 1 and 1 a includesimilar parts. The same or similar parts will be illustrated in FIGS.1-3 with the same number and described below. The light-emitting device1 or 1 a includes a substrate 11 a; one or more semiconductor structures1000 a on the substrate 11 a; and a surrounding part 111 a at and/orsurrounding the one or more semiconductor structures 1000 a. Each of theone or more semiconductor structures 1000 a includes a semiconductorstack 10 a including a first semiconductor layer 101 a, a secondsemiconductor layer 102 a, and an active layer 103 a between the firstsemiconductor layer 101 a and the second semiconductor layer 102 a. Asshown in FIG. 1 , FIG. 2 and FIG. 3 , parts of the second semiconductorlayer 102 a and the active layer 103 a at and/or around an outerperiphery of the one or more semiconductor structures 1000 a are removedto expose a first surface 1011 a of the first semiconductor layer 101 a.In one embodiment, a part of the first semiconductor layer 101 a can befurther removed to expose an exposed surface 11 s of the substrate 11 a.The first surface 1011 a is disposed at and/or along the outer peripheryof the one or more semiconductor structures 1000 a. In other words, thesurrounding part 111 a includes the first surface 1011 a of the firstsemiconductor layer 101 a which is a part of the semiconductor structure1000 a and/or the exposed surface 11 s of the substrate 11 a. So thesurrounding part 111 a is at and/or surrounds the outer periphery of thesemiconductor structure 1000 a.

The light-emitting device 1 or 1 a further includes one or moreopenings, such as vias 100 a passing through the second semiconductorlayer 102 a and the active layer 103 a to expose one or more secondsurfaces 1012 a of the first semiconductor layer 101 a; and a contactlayer 60 a including a first contact part 601 a and a second contactpart 602 a. The first contact part 601 a is formed on the first surface1011 a of the first semiconductor layer 101 a to surround the activelayer 103 a and at the outer periphery of the semiconductor structure1000 a. The first contact part 601 a contacts the first semiconductorlayer 101 a to form an electrical connection therewith. The firstcontact part 601 a is also formed on the one or more second surfaces1012 a of the first semiconductor layer 101 a to cover the one ormultiple vias 100 a and contact the first semiconductor layer 101 a toform an electrical connection therewith. In the present embodiment, inthe top view of the light-emitting device 1 or 1 a, the contact layer 60a includes a total surface area larger than a total surface area of theactive layer 103 a, and/or the contact layer 60 a includes a peripherallength larger than a peripheral length of the active layer 103 a. In oneembodiment of the present application, the contact layer 60 a furtherincludes a pin region 600 a and that will be described latter. In oneembodiment of the present application, the opening includes a trench. Inone embodiment, the multiple semiconductor structures 1000 a areseparated by the one or more openings, such as the trench, or connectedto each other by the first semiconductor layer 101 a. In one embodiment,the multiple semiconductor structures 1000 a are physically separated bythe one or more openings without the first semiconductor layer 101 aconnecting, and the one or more openings expose the substrate 11 a.

In an embodiment of the present application, the substrate 11 a can be agrowth substrate for epitaxial growth of the semiconductor stack 10 a,including gallium arsenide (GaAs) wafer for growing aluminum galliumindium phosphide (AlGaInP), sapphire (Al₂O₃) wafer, gallium nitride(GaN) wafer or silicon carbide (SiC) wafer for growing aluminum galliumindium nitride (AlGaInN).

In an embodiment of the present application, the substrate 11 a includesa texture surface between the semiconductor structures 1000 a and thesubstrate 11 a, which can enhance the light extraction efficiency of thelight-emitting device. The exposed surface 11 s of the substrate 11 aalso includes a texture surface (not shown). Various configurations oftexturing can be adopted, including random texturing, microlenses,microarrays, scattering regions or other optical regions. For example,the texture surface includes a plurality of protrusions, eachprotrusions may be about 0.5˜2.5 μm in height, 1˜3.5 μm in width andabout 1˜3.5 μm in pitch.

In an embodiment of the present application, the substrate 11 a includesa sidewall, the sidewall includes a flat surface and/or a rough surfaceto enhance the light-extraction efficiency of the light-emitting device.In an embodiment of the present application, the sidewall of thesubstrate 11 a can be inclined to a surface of the substrate 11 aadjoined to the semiconductor structures 1000 a to adjust the opticalfield distribution of the light-emitting device.

In an embodiment of the present application, the semiconductor stack 10a includes optical characteristics, such as light-emitting angle orwavelength distribution, and electrical characteristics, such as forwardvoltage or reverse current. The semiconductor stack 10 a can be formedon the substrate 11 a by organic metal chemical vapor deposition(MOCVD), molecular beam epitaxy (MBE), hydride vapor deposition (HVPE),or ion plating, such as sputtering or evaporation.

In an embodiment of the present application, the first semiconductorlayer 101 a and the second semiconductor layer 102 a, such as a claddinglayer, have different conductivity types, electrical properties,polarities, or doping elements for providing electrons or holes. Forexample, the first semiconductor layer 101 a is an n-type semiconductorand the second semiconductor layer 102 a is a p-type semiconductor. Theactive layer 103 a is formed between the first semiconductor layer 101 aand the second semiconductor layer 102 a. The electrons and holescombine in the active layer 103 a under a current driving to convertelectric energy into light energy and then light is emitted from theactive layer 103 a. The wavelength of the light emitted from thelight-emitting device 1 or the light-emitting device 1 a is adjusted bychanging the physical and chemical composition of one or more layers inthe semiconductor stack 10 a. The material of the semiconductor stack 10a includes a group III-V semiconductor material, such asAl_(x)In_(y)Ga_((1-x-y))N or Al_(x)In_(y)Ga_((1-x-y))P, wherein 0≤x,y≤1; (x+y)≤1. According to the material of the active layer 103 a, whenthe material of the semiconductor stack 10 a is AlInGaP series material,red light having a wavelength between 610 nm and 650 nm or yellow lighthaving a wavelength between 550 nm and 570 nm can be emitted. When thematerial of the semiconductor stack 10 a is InGaN series material, blueor deep blue light having a wavelength between 400 nm and 490 nm orgreen light having a wavelength between 490 nm and 550 nm can beemitted. When the material of the semiconductor stack 10 a is AlGaNseries material, UV light having a wavelength between 400 nm and 250 nmcan be emitted. The active layer 103 a can be a single heterostructure(SH), a double heterostructure (DH), a double-side doubleheterostructure (DDH), or a multi-quantum well structure, MQW). Thematerial of the active layer 103 a can be i-type, p-type, or n-typesemiconductor.

In an embodiment of the present application, a buffer layer (not shown)is formed between the semiconductor stack 10 a and the substrate 11 a toimprove the epitaxial quality of the semiconductor stack 10 a. In anembodiment, aluminum nitride (AlN) can be used as the buffer layer. Inan embodiment, the method for forming aluminum nitride (AlN) is PVD, andthe target is made of aluminum nitride. In another embodiment, a targetmade of aluminum which reacts in a nitrogen source environment with aPVD method is used to form aluminum nitride.

In an embodiment of the present application, the semiconductor stack 10a includes a first outside wall 1003 a and a second outside wall 1001 a,wherein one end of the first surface 1011 a is connected to the firstoutside wall 1003 a, and another end of the first surface 1011 a isconnected to the second outside wall 1001 a. As shown in FIGS. 2-3 , thefirst outside wall 1003 a and the second outside wall 1001 a bothincline to the first surface 1011 a. In another embodiment, the firstoutside wall 1003 a is approximately perpendicular to the first surface1011 a, and the second outside wall 1001 a is inclined to the firstsurface 1011 a. In one embodiment, the first outside wall 1003 ainclines to the exposed surface 11 s of the substrate 11 a. An anglebetween the first outside wall 1003 a and the exposed surface 11 sincludes an acute angle. In one embodiment, an angle between the firstoutside wall 1003 a and the exposed surface 11 s includes an obtuseangle.

In an embodiment of the present application, as shown in FIGS. 2-3 , thevia 100 a is defined by an inside wall 1002 a and the second surface1012 a, wherein the inside wall 1002 a exposes the second semiconductorlayer 102 a and the active layer 103 a, and the second surface 1012 aexposes the first semiconductor layer 101 a. One end of the inside wall1002 a is connected to the second surface 1012 a of the firstsemiconductor layer 101 a and another end of the inside wall 1002 a isconnected to a surface 102 s of the second semiconductor layer 102 a.

In an embodiment of the present application, the light-emitting device 1or 1 a includes a first insulating structure 20 a formed on thesemiconductor structure 1000 a by sputtering or vapor deposition. Thefirst insulating structure 20 a is formed on the first surface 1011 a ofthe surrounding part 111 a, extending along the second outside wall 1001a and onto the surface 102 s of the second semiconductor layer 102 a.The first insulating structure 20 a is also formed on the second surface1012 a of the via 100 a, extending along the inside wall 1002 a and ontothe surface 102 s of the second semiconductor layer 102 a. In oneembodiment, the first insulating structure 20 a includes one layer ormultiple layers. The first insulating structure 20 a protects thesidewall of the semiconductor structure 1000 a to prevent the activelayer 103 a from being destroyed by the following processes. When thefirst insulating structure 20 a includes multiple layers, the firstinsulating structure 20 a includes two or more layers having differentrefractive indexes alternately stacked to form a Distributed Braggreflector (DBR). The DBR can protects the sidewalls of the semiconductorstructure 1000 a, and can further selectively reflect light of aspecific wavelength emitted from the active layer 103 a to outside ofthe light-emitting device 1 or 1 a to enhance brightness. The firstinsulating structure 20 a is formed of a non-conductive materialincluding organic material, inorganic material or dielectric material.The organic material includes Su8, benzocyclobutene (BCB),perfluorocyclobutane (PFCB), epoxy resin, acrylic resin, cyclic olefinpolymers (COC), polymethylmethacrylate (PMMA), polyethyleneterephthalate (PET), polycarbonate (PC), polyetherimide, or fluorocarbonpolymer. The inorganic material includes silicone, glass. The dielectricmaterial includes aluminum oxide (Al₂O₃), silicon nitride (SiN_(x)),silicon oxide (SiO_(x)), titanium oxide (TiO_(x)), or magnesium fluoride(MgF_(x)).

The first insulating structure 20 a includes one or multiple firstinsulating first openings 201 a to expose the first semiconductor layer101 a, and one or multiple first insulating second openings 202 a toexpose the second semiconductor layer 102 a.

In an embodiment of the present application, the light-emitting device 1or 1 a includes a transparent conductive layer 30 a formed on thesurface 102 s of the second semiconductor layer 102 a. An outer edge 301a of the transparent conductive layer 30 a is spaced apart from thefirst insulating structure 20 a with a distance to expose the surface102 s of the second semiconductor layer 102 a. Namely, the firstinsulating second opening 202 a of the first insulating structure 20 aexposes the second semiconductor layer 102 a, and the transparentconductive layer 30 a is formed in the first insulating second opening202 a to contact the second semiconductor layer 102 a.

Since the transparent conductive layer 30 a is substantially formed onan entire surface of the second semiconductor layer 102 a and contactsthe second semiconductor layer 102 a, the current can be uniformlyspread throughout the entire second semiconductor layer 102 a by thetransparent conductive layer 30 a. The material of the transparentconductive layer 30 a includes a material being transparent to the lightemitted from the active layer 103 a, such as indium tin oxide (ITO) orindium zinc oxide (IZO).

In an embodiment of the present application, the light-emitting device 1or 1 a includes a reflective structure formed on the transparentconductive layer 30 a. The reflective structure includes a reflectivelayer 40 a, a barrier layer 41 a or a combination of the above. An outeredge 401 a of the reflective layer 40 a can be disposed on the innerside or the outer side of the outer edge 301 a of the transparentconductive layer 30 a, or disposed to overlap and aligned with the outeredge 301 a of the transparent conductive layer 30 a. An outer edge (notshown) of the barrier layer 41 a can be disposed on the inner side orthe outer side of the outer edge 401 a of the reflective layer 40 a orprovided to overlap and aligned with the outer edge 401 a of thereflective layer 40 a.

In an embodiment of the present application, the outer edge 301 a of thetransparent conductive layer 30 a overlaps the first insulatingstructure 20 a. Namely, the first insulating second opening 202 a of thefirst insulating structure 20 a exposes the second semiconductor layer102 a, and the transparent conductive layer 30 a is formed in the firstinsulating second opening 202 a to contact the second semiconductorlayer 102 a, and extends from the portion in the first insulating secondopening 202 a onto the first insulating second opening 202 a. The outeredge 401 a of the reflective layer 40 a can be disposed on the innerside or the outer side of the outer edge 301 a of the transparentconductive layer 30 a. The reflective layer 40 a is disposed to overlapthe first insulating structure 20 a.

In an embodiment of the present application, the light-emitting device 1or 1 a does not include the transparent conductive layer 30 a and thereflective structure is directly formed on the surface 102 s of thesecond semiconductor layer 102 a.

In an embodiment of the present application, the reflective layer 40 aincludes one layer or multiple sub-layers, such as a Distributed Braggreflector (DBR).

In an embodiment of the present application, the material of thereflective layer 40 a includes a metal material having a highreflectance, for example, silver (Ag), aluminum (Al), rhodium (Rh), oran alloy of the above materials. The high reflectance referred to hereinmeans having 80% or more reflectance for a wavelength of a light emittedfrom the light-emitting device 1 or 1 a.

In an embodiment of the present application, the barrier layer 41 acovers the reflective layer 40 a to prevent the surface of thereflective layer 40 a from being oxidized that deteriorates thereflectivity of the reflective layer 40 a. The material of the barrierlayer 41 a includes metal material, such as titanium (Ti), tungsten (W),aluminum (Al), indium (In), tin (Sn), nickel (Ni), platinum (Pt), or analloy of the above materials. The barrier layer 41 a includes one layeror multiple sub-layers, such as titanium (Ti)/aluminum (Al) and/ortitanium (Ti)/tungsten (W). In an embodiment of the present application,the barrier layer 41 a includes titanium (Ti)/aluminum (Al) on one sideof the barrier layer 41 a away from the reflective layer 40 a andtitanium (Ti)/tungsten (W) on another side of the barrier layer 41 aadjacent to the reflective layer 40 a. In one embodiment of the presentapplication, the material of the reflective layer 40 a and the barrierlayer 41 a preferably includes a metal material other than gold (Au) orcopper (Cu).

In an embodiment of the present application, the light-emitting device 1or 1 a includes a second insulating structure 50 a formed on thesemiconductor structure 1000 a by sputtering or vapor deposition. Thesecond insulating structure 50 a includes one or multiple secondinsulating first openings 501 a to expose the first semiconductor layer101 a and one or multiple second insulating second openings 502 a toexpose the reflective layer 40 a, the barrier layer 41 a and/or thetransparent conductive layer 30 a.

In an embodiment of the present application, parts of the transparentconductive layer 30 a, the reflective layer 40 a, the barrier layer 41 aand/or the first insulating structure 20 a are partially covered by thesecond insulating structure 50 a. Other parts of the transparentconductive layer 30 a, the reflective layer 40 a, the barrier layer 41 aand/or the first insulating structure 20 a are totally covered by thesecond insulating structure 50 a.

In an embodiment of the present application, a part of the secondinsulating structure 50 a is formed in the first insulating secondopening 202 a and directly contacts the surface 102 s of the secondsemiconductor layer 102 a.

In an embodiment of the present application, the second insulating firstopenings 501 a and the second insulating second openings 502 a includedifferent widths or numbers. The opening shapes of the second insulatingfirst openings 501 a and the second insulating second openings 502 ainclude circular, elliptical, rectangular, polygonal, or arbitraryshape. A position of the one or multiple second insulating firstopenings 501 a is formed to correspond to a position of the via 100 a.

In an embodiment of the present application, the one second insulatingsecond opening 502 a is a groove surrounding a portion 500 a of thesecond insulating structure 50 a in the top view of the light-emittingdevice 1 or 1 a.

In an embodiment of the present application, the second insulatingstructure 50 a includes one layer or multiple layers. The secondinsulating structure 50 a protects the sidewalls of the semiconductorstructure 1000 a to prevent destruction of the active layer 103 a bysubsequent processes. When the second insulating structure 50 a includesmultiple layers, the second insulating structure 50 a includes two ormore layers having different refractive index materials alternatelystacked to form a Distributed Bragg reflector (DBR) The DBR can protectsthe sidewalls of the semiconductor structure 1000 a and can furtherselectively reflect light of a specific wavelength emitted from theactive layer 103 a to outside of the light-emitting device 1 or 1 a toenhance brightness. The second insulating structure 50 a is formed of anon-conductive material including organic material, inorganic materialor dielectric material. The organic material includes Su8,benzocyclobutene (BCB), perfluorocyclobutane (PFCB), epoxy resin,acrylic resin, cyclic olefin polymers (COC), polymethylmethacrylate(PMMA), polyethylene terephthalate (PET), polycarbonate (PC),polyetherimide, or fluorocarbon polymer. The inorganic material includessilicone or glass. The dielectric material includes aluminum oxide(Al₂O₃), silicon nitride (SiN_(x)), silicon oxide (SiO_(x)), titaniumoxide (TiO_(x)), or magnesium fluoride (MgF_(x)). The Distributed Braggreflector (DBR) includes a low refractive index layer and a highrefractive index layer, the material of the high refractive index layeris selected from TiO₂, ZnSe, Si₃N₄, Nb₂O₅, or Ta₂O₅, and the material ofthe low refractive index layer is selected from SiO₂, MgF₂, or CaF₂.

In an embodiment of the present application, the first insulatingstructure 20 a comprises a material different from that of the secondinsulating structure 50 a. For example, the first insulating structure20 a comprises Si₃N₄, and the second insulating structure 50 a comprisesSiO₂. Since Si₃N₄ has a higher etching selectivity than SiO₂, the firstinsulating structure 20 a including Si₃N₄ is used to be a mask forforming the one or more semiconductor structures 1000 a. Because SiO₂has a better step coverage rate than Si₃N₄, the second insulatingstructure 50 a including SiO₂ is used as a protecting layer covering theside surface of the second semiconductor layer 102 a and the activelayer 103 a.

In an embodiment of the present application, the contact layer 60 a canbe formed on the first semiconductor layer 101 a and the secondsemiconductor layer 102 a by sputtering or vapor deposition. In oneembodiment, the first contact part 601 a of the contact layer 60 a canbe a first electrode and the second contact part 602 a can be a secondelectrode. The first electrode 601 a and the second electrode 602 a areused for connecting an outside power supplier by wire bonding or solderbumping. The first electrode 601 a is formed in the via 100 a, andextends along the inside wall 1002 a and onto a surface of the secondinsulating structure 50 a. The first electrode 601 a formed at the via100 a and the second insulating first openings 501 a contacts the firstsemiconductor layer 101 a and electrically connected to the firstsemiconductor layer 101 a. The second electrode 602 a is formed on thesemiconductor structure 1000 a, and the portion 500 a of the secondinsulating structure 50 a is formed therebetween. The second electrode602 a extends from the part on the portion 500 a into the secondinsulating second opening 502 a to contact the reflective layer 40 a,the barrier layer 41 a or the transparent conductive layer 30 a. Thesecond electrode 602 a is electrically connected to the secondsemiconductor layer 102 a through the reflective layer 40 a, the barrierlayer 41 a or the transparent conductive layer 30 a.

In an embodiment of the present application, the light-emitting device 1includes a third insulating structure 70 a formed by sputtering or vapordeposition and covering the first electrode 601 a, the second electrode602 a and the semiconductor stack 10 a. The third insulating structure70 a includes a first opening 701 a to expose the first electrode 601 aand a second opening 702 a to expose the second electrode 602 a. Thethird insulating structure 70 a includes one layer or multiple layers.The third insulating structure 70 a can protect the sidewalls of thesemiconductor structure 1000 a to prevent destruction of the activelayer 103 a by subsequent processes. When the third insulating structure70 a includes multiple layers, the third insulating structure 70 aincludes two or more layers having different refractive indexalternately stacked to form a Distributed Bragg reflector (DBR) The DBRcan protect the sidewalls of the semiconductor structure 1000 a and canfurther reflect light of a specific wavelength emitted from the activelayer 103 a to outside of the light-emitting device 1 or 1 a to enhancebrightness. The third insulating structure 70 a is formed of anon-conductive material including organic material, inorganic materialor dielectric material. The organic material includes Su8,benzocyclobutene (BCB), perfluorocyclobutane (PFCB), epoxy resin,acrylic resin, cyclic olefin polymers (COC), polymethylmethacrylate(PMMA), polyethylene terephthalate (PET), polycarbonate (PC),polyetherimide, or fluorocarbon polymer. The inorganic material includessilicone or glass. The dielectric material includes aluminum oxide(Al₂O₃), silicon nitride (SiN_(x)), silicon oxide (SiO_(x)), titaniumoxide (TiO_(x)), or magnesium fluoride (MgF_(x)).

In an embodiment of the present application, the contact layer 60 afurther includes the pin region 600 a surrounded and covered by thethird insulating structure 70 a. In an embodiment, the pin region 600 aincludes same materials as that of the first electrode 601 a and thesecond electrode 602 a. The pin region 600 a is electrically isolated tothe semiconductor stack 10 a by the second insulating structure 50 a andthe third insulating structure 70 a. The pin region 600 a is separatedapart from the first electrode 601 a and the second electrode 602 a bythe third insulating structure 70 a. From a top view of thelight-emitting device 1, the light-emitting device 1 includes arectangular shape having four corners. The pin region 600 a is locatedat or near an intersection of two diagonals of the rectangular shape.

In an embodiment of the present application, the first electrode 601 aand/or the second electrode 602 a includes one layer or multiple layers.In an embodiment, in order to improve the adhesion between thereflective structure and the contact layer 60 a, the first electrode 601a and/or the second electrode 602 a includes an adhesive layer closestto the first semiconductor layer 101 a or the second semiconductor layer102 a. The material of the adhesive layer includes chromium (Cr),titanium (Ti) or rhodium (Rh). In an embodiment, in order to improve thereflectivity of the contact layer 60 a, the first electrode 601 a and/orthe second electrode 602 a includes a reflecting layer above theadhesive layer. The material of the reflecting layer includes aluminum(Al) or silver (Ag). In an embodiment, in order to improve a bondingstrength between the contact layer 60 a and the solder (not shown)and/or a bonding strength between the contact layer 60 a and the thirdinsulating structure 70 a, the first electrode 601 a and/or the secondelectrode 602 a includes a bonding layer. The bonding layer includes ametal material including a surface tension value larger than 1500dyne/cm and a standard reduction potential larger than 0.3 V. Forexample, the bonding layer includes platinum (Pt). The value of thestandard reduction potential is given in voltage (V) relative to thestandard hydrogen electrode at a temperature of 298.15 K (25° C.) and ata pressure of 101.325 kPa (1 atm). In an embodiment, the bonding layerincludes a metal material having a positive standard reduction potentialin respect to the standard hydrogen electrode under a reduction reactionof metal element. The surface tension value is measured in force perunit length at the melting point of the metal material.

In an embodiment of the present application, in order to avoid of acrack penetrated from the contact layer 60 a into the semiconductorstructure 1000 a when the contact layer 60 a is bonded to a packagecarrier, the bonding layer preferably includes an enough stiffness toafford the bonding strength. In an embodiment, the bonding layerincludes a metal material including a Young's modulus value larger than100 GPa. For example, the bonding layer includes platinum (Pt).

In an embodiment of the present application, in order to improve thelight extraction of the light-emitting device 1 via increasing thereflectivity of the contact layer 60 a, the first electrode 601 a andthe second electrode 602 a occupy 40% above of the light-emitting areaof the light-emitting device 1. The first electrode 601 a and the secondelectrode 602 a are separated apart by a distance smaller than 50 μm. Inan embodiment, the distance is smaller than 30 μm. In an embodiment, thedistance is smaller than 10 μm. From a top view of the light-emittingdevice 1, the second electrode 602 a includes a surface area smallerthan a surface of the first electrode 601 a. The second electrode 602 ais surrounded by the first electrode 601 a. In an embodiment, a portionof the first electrode 601 a formed on the surrounding part 111 aencloses the semiconductor structure 1000 a.

In an embodiment, the first electrode 601 a is formed on the surroundingpart 111 a, extends from the first surface 1011 a of the firstsemiconductor layer 101 a, along the second outside wall 1001 a tooverlap the surface 102 s of the second semiconductor layer 102 a.

In an embodiment, the first electrode 601 a is formed on the surroundingpart 111 a, extends from the exposed surface 11 s of the substrate 11 a,along the first surface 1011 a of the first semiconductor layer 101 aand the second outside wall 1001 a, to overlap the surface 102 s of thesecond semiconductor layer 102 a.

In an embodiment of the present application, in order to improve thebonding strength between the contact layer 60 a and solder bumps, thefirst electrode 601 a and/or the second electrode 602 a includes athickness between 1 μm and 3 μm.

In an embodiment of the present application, as shown in FIG. 3 , thestructure of the light-emitting device 1 a is similar to that of thelight-emitting device 1. The light-emitting device 1 a further includesa first thin pad 80 a formed in the first opening 701 a of the thirdinsulating structure 70 a and on the first electrode 601 a, and a secondthin pad 90 a formed in the second opening 702 a of the third insulatingstructure 70 a and on the second electrode 602 a. The first thin pad 80a has a thickness smaller than a thickness of the third insulatingstructure 70 a. The second thin pad 90 a having a thickness smaller thana thickness of the third insulating structure 70 a. For example, thefirst thin pad 80 a and/or the second thin pad 90 a includes a thicknessbetween 0.1 μm and 1 μm, the third insulating structure 70 a includes athickness between 0.5 μm and 2.5 μm.

In an embodiment of the present application, in order to reduce a heightdifference between the first electrode 601 a and the second electrode602 a, the second insulating structure 50 a further includes the portion500 a formed under the second electrode 602 a. Multiple sidewalls of theportion 500 a of the second insulating structure 50 a are covered by thesecond electrode 602 a.

In an embodiment of the present application, in order to preventelectrical short between the first electrode 601 a and the secondelectrode 602 a, the second opening 702 a of the third insulatingstructure 70 a is narrower than the second insulating second opening 502a of the second insulating structure 50 a, and the second insulatingsecond opening 502 a of the second insulating structure 50 a is narrowerthan the first insulating second opening 202 a of the first insulatingstructure 20 a. Specifically, part of the third insulating structure 70a is formed in the second insulating second openings 502 a of the secondinsulating structure 50 a. The third insulating structure 70 a alsoextends onto the second electrode 602 a. The second opening 702 a of thethird insulating structure 70 a is formed on a top surface of the secondelectrode 602 a.

In an embodiment of the present application, in order to increase theexposed surface of the second electrode 602 a for flipping bonding, suchas eutectic bonding or solder bumping, the second opening 702 a of thethird insulating structure 70 a is wider than the second insulatingsecond opening 502 a of the second insulating structure 50 a, and thesecond insulating second opening 502 a of the second insulatingstructure 50 a is narrower or wider than the first insulating secondopening 202 a of the first insulating structure 20 a.

In an embodiment of the present application, as shown in FIG. 3 , a topsurface of the first thin pad 80 a or the second thin pad 90 a is lowerthan a top surface of the third insulating structure 70 a. An entiretyof the first thin pad 80 a or the second thin pad 90 a is formed insidethe first opening 701 a or the second opening 702 a.

In an embodiment of the present application, a top surface of the firstthin pad 80 a or the second thin pad 90 a is higher than a top surfaceof the third insulating structure 70 a. The first thin pad 80 a or thesecond thin pad 90 a is formed in the first opening 701 a or the secondopening 702 a and extends onto the top surface of the third insulatingstructure 70 a.

In an embodiment of the present application, part of first thin pad 80 aand/or the second thin pad 90 a extending onto the top surface of thethird insulating structure 70 a includes a thickness thicker than athickness of the third insulating structure 70 a.

In an embodiment of the present application, the first thin pad 80 aincludes a projected surface on the substrate 11 a which is smaller thana projected surface of the first contact part 601 a on the substrate 11a. The second thin pad 90 a includes a projected surface on thesubstrate 11 a which is smaller or larger than a projected surface ofthe second contact part 602 a on the substrate 11 a.

In an embodiment of the present application, the first thin pad 80 a andthe second thin pad 90 a are separated apart by a distance larger than50 μm, the pin region 600 a is disposed between the first thin pad 80 aand the second thin pad 90 a, and also between the first contact part601 a and the second contact part 602 a. In other words, the pin region600 a is not covered by the first thin pad 80 a and the second thin pad90 a, and also separated from the first contact part 601 a and thesecond contact part 602 a.

FIG. 4 illustrates a top view of the light-emitting device 2 inaccordance with an embodiment of the present application. For clearillustration, each layer is drawn in solid line regardless of itsmaterial being non-transparent, transparent, or semi-transparent.

The light-emitting device 2 includes the substrate, the semiconductorstructure 1000 a, a first electrode 601A and a second electrode 602A,and the third insulating structure 70 a. The substrate (not shown), thesemiconductor structure 1000 a and the third insulating structure 70 aof the light-emitting device 2 are similar to those of thelight-emitting devices 1 and 1 a. In order to improve the lightextraction and the current spreading of the light-emitting device 2, thelight-emitting device 2 includes the first electrode 601A and the secondelectrode 602A, wherein the first electrode 601A and the secondelectrode 602A occupy 10˜20% of the light-emitting area of thelight-emitting device 2. The first electrode 601A includes a firstbonding pad 6010 and one or multiple first extensions 6011 extendingfrom the first bonding pad 6010. The second electrode 602A includes asecond bonding pad 6020 and one or multiple second extensions 6021extending from the second bonding pad 6020. The multiple firstextensions 6011 and the multiple second extensions 6021 are notoverlapped.

The third insulating structure 70 a covers the top surface and the sidesurfaces of the semiconductor structure 1000 a. In this embodiment, thefirst electrode 601A has two first extensions 6011 and the secondelectrode 602A has two second extensions 6021. The third insulatingstructure 70 a also covers the first extensions 6011 and the secondextensions 6021 and exposes partial surfaces of the first bonding pad6010 (the hatch area) and the second bonding pad 6020 (the hatch area)by the first opening 701 a and the second opening 702 a respectively. Inan embodiment, the first semiconductor layer 101 a is an n-typesemiconductor, and the second semiconductor layer 102 a is a p-typesemiconductor. The n-type semiconductor and the p-type semiconductor arecovered by the third insulating structure 70 a (referring to FIG. 3 ).

In one embodiment, each of the first bonding pad 6010 and the secondbonding pad 6020 includes a metal multilayer, for exampleCr/Al/Cr/Al/Ni/Pt, Cr/Al/Cr/Al/Ni/Au, Cr/Al/Cr/Al/Ni/Pt/Au, orTi/Al/Ti/Al/Ni/Pt/Au, and the Pt or Au layer directly contacts the thirdinsulating structure 70 a and the metal bumps 902 a, 902 b (shown inFIG. 4C or 4D). Since the Pt or Au layer will react with the metal bumps(for example, solder) to form intermetallic compounds (IMCs), the Pt orAu layer may not be observed by Scanning Electron Microscope (SEM) orthe IMCs layer is observed by SEM. In an embodiment, the IMCs layer isalso not observed by SEM and the Ni layer directly contacts the metalbumps while analyzed by SEM. In an embodiment, the Pt or Au layer maynot completely react with the metal bumps and the Pt or Au layer isobserved by SEM.

FIG. 5 is a schematic view of a light-emitting apparatus 3 in accordancewith an embodiment of the present application. The light-emitting device1, 1 a, or 2 in the foregoing embodiment is mounted on the first spacer511 and the second spacer 512 of the package substrate 51 in the form offlip chip. The first spacer 511 and the second spacer 512 areelectrically insulated from each other by an insulating portion 53including an insulating material. The main light-extraction surface ofthe flip-chip is one side of the growth substrate 11 a opposite to theelectrode-forming surface. A reflective structure 54 can be providedaround the light-emitting device to increase the light extractionefficiency of the light-emitting apparatus 3.

FIG. 6 illustrates a structure diagram of a light-emitting apparatus 4in accordance with an embodiment of the present application. A lightbulb includes an envelope 602, a lens 604, a light-emitting module 610,a base 612, a heat sink 614, a connector 616 and an electricalconnecting device 618. The light-emitting module 610 includes a submount606 and a plurality of light-emitting devices 608 on the submount 606,wherein the plurality of light-emitting devices 608 can be thelight-emitting devices 1, 1 a, 2 or the light-emitting apparatus 3described in above embodiments.

The principle and the efficiency of the present application illustratedby the embodiments above are not the limitation of the application. Anyperson having ordinary skill in the art can modify or change theaforementioned embodiments. Therefore, the protection range of therights in the application will be listed as the following claims.

What is claimed is:
 1. A light-emitting device, comprising: asemiconductor structure comprising a first semiconductor layer, a secondsemiconductor layer, and an active layer between the first semiconductorlayer and the second semiconductor layer; a via passing through thesecond semiconductor layer and the active layer to expose a firstsurface of the first semiconductor layer; an insulating structurecovering the semiconductor structure, the insulating structurecomprising a first opening on the first surface, and a second opening onthe second semiconductor layer, wherein the insulating structurecomprises a thickness; a first pad formed in the first opening of theinsulating structure to electrically connect to the first semiconductorlayer through the via and extending onto the insulating structure,wherein the first pad comprises a thickness; and a second pad formed inthe second opening of the insulating structure to electrically connectto the second semiconductor layer and extending onto the insulatingstructure, wherein the second pad comprises a thickness, the thicknessof the first pad and/or the thickness of the second pad is smaller thanthe thickness of the insulating structure.
 2. The light-emitting deviceaccording to claim 1, wherein the insulating structure comprises aDistributed Bragg reflector (DBR).
 3. The light-emitting deviceaccording to claim 1, wherein the insulating structure comprises a sidesurface and a top surface connected to the side surface.
 4. Thelight-emitting device according to claim 3, wherein an entirety of thefirst pad is formed inside the first opening and extends to and contactsto the side surface, or an entirety of the second pad is formed insidethe second opening and extends to and contacts to the side surface. 5.The light-emitting device according to claim 3, wherein the first pad orthe second pad comprises a first top surface, and the first top surfaceis lower than the top surface of the insulating structure.
 6. Thelight-emitting device according to claim 3, wherein the first pad or thesecond pad comprises a second top surface, and the second top surface ishigher than a top surface of the insulating structure.
 7. Thelight-emitting device according to claim 1, wherein the first pad andthe second pad are separated apart by a distance larger than 50 μm. 8.The light-emitting device according to claim 1, further comprising afirst electrode formed on the first semiconductor layer and a secondelectrode formed on the second semiconductor layer.
 9. Thelight-emitting device according to claim 8, wherein the first electrodeand the second electrode are not overlapped in a cross-sectional view ofthe light-emitting device.
 10. The light-emitting device according toclaim 9, wherein the first electrode and the second electrode areseparated apart by a distance smaller than 50 μm.
 11. The light-emittingdevice according to claim 8, wherein the first electrode and/or thesecond electrode comprises an adhesive layer comprising a metal materialselected from a group consisting of chromium (Cr), titanium (Ti) andrhodium (Rh).
 12. The light-emitting device according to claim 11,wherein the first electrode and/or the second electrode comprises areflective layer formed on the adhesive layer comprising a metalmaterial selected from a group consisting of aluminum (Al) and silver(Ag).
 13. The light-emitting device according to claim 8, wherein thefirst electrode and/or the second electrode comprises a bonding layercomprising a metal material comprising a Young's modulus value largerthan 100 GPa.
 14. The light-emitting device according to claim 8,wherein the first electrode and/or the second electrode comprises abonding layer comprising a metal material comprising a surface tensionvalue larger than 1500 dyne/cm and a standard reduction potential largerthan 0.3 V.
 15. The light-emitting device according to claim 12, whereinthe first electrode and/or the second electrode comprises a bondinglayer formed on the reflective layer comprising Pt.
 16. Thelight-emitting device according to claim 1, further comprising a texturesurface on a side of the semiconductor structure opposed to the firstpad.
 17. The light-emitting device according to claim 1, furthercomprising a substrate, wherein the texture surface is between thesemiconductor structure and the substrate.
 18. The light-emitting deviceaccording to claim 17, wherein the substrate comprises an exposedsurface not covered by the semiconductor structure and the insulatinglayer.
 19. The light-emitting device according to claim 8, wherein thefirst electrode and the second electrode occupy 40% above of alight-emitting area of the light-emitting device.
 20. The light-emittingdevice according to claim 8, wherein the first electrode and the secondelectrode occupy 10˜20% of a light-emitting area of the light-emittingdevice.